I set mine up a while back, I can’t remeber if I installed windows 10 on bare metal or in the VM. I remember I tried both, I want to say installing in the VM worked better. But what I do, is first set up KVM/qemu with virtual machine manager. Then IF YOU DONT HAVE WINDOWS ALREADY wipe the drive you want for windows. I usually just wipe and leave it as free space and not create a partition. Then in virtual machine manager, create a new virtual machine. Use local install media as the install option, select your windows ISO, then instead of ‘create disk image for virtual machine’, you check 'select or create custom storage and type in /dev/nvme1n1 or whatever the drive address is. check the customize before install and make sure its using UEFI instead of BIOS.

IF YOU ALREADY HAVE WINDOWS INSTALLED, open virtual machine manager, add new virtual machine, manual install, select or create custom storage, then type ‘/dev/nvme1n1’ or whatever your address is. Check the custumize configuration before install and make sure its using UEFI instead of BIOS.

for both you’ll want to install the KVM windows drivers you can find them on github